From the TITAN web page:
Titan is a collection of programs, each of which either fixes or
tightens one or more potential security problems with a
particular aspect in the setup or configuration of a Unix
system. Conceived and created by Brad Powell, it was written in
Bourne shell, and its simple modular design makes it trivial for
anyone who can write a shell script or program to add to it, as
well completely understand the internal workings of the system.
A similar tool is Bastille Linux.
Medusa consists of two major parts - linux kernel changes and the user-space daemon. Kernel changes do the monitoring of syscalls, filesystem actions, processes and they implement the communication protocol. Security daemon communicates with the kernel using character device to send and receive "packets". Daemon contains the whole logic and implements the concrete security policy. That means, that medusa can (as opposite to another approaches) implement any model of data protection - it depends only on configuration file, which is in fact an program in the internal programming language, somewhat similar to C.